Navigation device and method for early instruction output

ABSTRACT

A method and device are disclosed for navigation. In at least one embodiment, the method includes determining, during a route of travel of a navigation device, entry of the navigation device into a tunnel; and outputting a navigation instruction to a user of the navigation device within the tunnel, for travel along the travel route, upon determining, subsequent to determining entry of the navigation device into the tunnel, at least one of the tunnel being longer than a first threshold distance, a navigation instruction being due to be output within a second threshold distance of an exit of the tunnel and the navigation instruction being due to be output within the tunnel. In at least one embodiment, the navigation device includes a processor to determine, during a route of travel of a navigation device, entry of the navigation device into a tunnel; and an output device to output a navigation instruction to a user of the navigation device within the tunnel, for travel along the travel route, upon the processor determining, subsequent to determining entry of the navigation device into the tunnel, at least one of the tunnel being longer than a first threshold distance, a navigation instruction being due to be output within a second threshold distance of an exit of the tunnel and the navigation instruction being due to be output within the tunnel.

CO-PENDING APPLICATIONS

The following applications are being filed concurrently with the presentapplication. The entire contents of each of the following applicationsis hereby incorporated herein by reference: A NAVIGATION DEVICE ANDMETHOD FOR ESTABLISHING AND USING PROFILES (Attorney docket number06P207US02) filed on even date herewith; A NAVIGATION DEVICE AND METHODFOR ENHANCED MAP DISPLAY (Attorney docket number 06P207US03) filed oneven date herewith; A NAVIGATION DEVICE AND METHOD RELATING TO ANAUDIBLE RECOGNITION MODE (Attorney docket number 06P207US04) filed oneven date herewith; NAVIGATION DEVICE AND METHOD FOR PROVIDING POINTS OFINTEREST (Attorney docket number 06P207US05) filed on even dateherewith; A NAVIGATION DEVICE AND METHOD FOR FUEL PRICING DISPLAY(Attorney docket number 06P057US06) filed on even date herewith; ANAVIGATION DEVICE AND METHOD FOR INFORMATIONAL SCREEN DISPLAY (Attorneydocket number 06P207US06) filed on even date herewith; A NAVIGATIONDEVICE AND METHOD FOR DEALING WITH LIMITED ACCESS ROADS (Attorney docketnumber 06P057US07) filed on even date herewith; A NAVIGATION DEVICE ANDMETHOD FOR TRAVEL WARNINGS (Attorney docket number 06PO57US07) filed oneven date herewith; A NAVIGATION DEVICE AND METHOD FOR DRIVING BREAKWARNING (Attorney docket number 06PO57US07) filed on even date herewith;A NAVIGATION DEVICE AND METHOD FOR ISSUING WARNINGS (Attorney docketnumber 06P207US07) filed on even date herewith; A NAVIGATION DEVICE ANDMETHOD FOR DISPLAY OF POSITION IN TEXT READIBLE FORM (Attorney docketnumber 06P207US08) filed on even date herewith; A NAVIGATION DEVICE ANDMETHOD FOR EMERGENCY SERVICE ACCESS (Attorney docket number 06PO57US08)filed on even date herewith; A NAVIGATION DEVICE AND METHOD FORPROVIDING REGIONAL TRAVEL INFORMATION IN A NAVIGATION DEVICE (Attorneydocket number 06P207US09) filed on even date herewith; A NAVIGATIONDEVICE AND METHOD FOR USING SPECIAL CHARACTERS IN A NAVIGATION DEVICE(Attorney docket number 06P207US09) filed on even date herewith; ANAVIGATION DEVICE AND METHOD USING A PERSONAL AREA NETWORK (Attorneydocket number 06P207US10) filed on even date herewith; A NAVIGATIONDEVICE AND METHOD USING A LOCATION MESSAGE (Attorney docket number06P207US10) filed on even date herewith; A NAVIGATION DEVICE AND METHODFOR CONSERVING POWER (Attorney docket number 06P207US11) filed on evendate herewith; A NAVIGATION DEVICE AND METHOD FOR USING A TRAFFICMESSAGE CHANNEL (Attorney docket number 06P207US13) filed on even dateherewith; A NAVIGATION DEVICE AND METHOD FOR USING A TRAFFIC MESSAGECHANNEL RESOURCE (Attorney docket number 06P207US13) filed on even dateherewith; A NAVIGATION DEVICE AND METHOD FOR QUICK OPTION ACCESS(Attorney docket number 06P207US15) filed on even date herewith; ANAVIGATION DEVICE AND METHOD FOR DISPLAYING A RICH CONTENT DOCUMENT(Attorney docket number 06P207US27) filed on even date herewith.

PRIORITY STATEMENT

The present application hereby claims priority under 35 U.S.C. § 119(e)on each of U.S. Provisional Patent Application Nos. 60/879,523 filedJan. 10, 2007, 60/879,549 filed Jan. 10, 2007, 60/879,553 filed Jan. 10,2007, 60/879,577 filed Jan. 10, 2007, and 60/879,599 filed Jan. 10,2007, the entire contents of each of which is hereby incorporated hereinby reference.

FIELD

The present application generally relates to navigation methods anddevices.

BACKGROUND

Navigation devices were traditionally utilized mainly in the areas ofvehicle use, such as on cars, motorcycles, trucks, boats, etc.Alternatively, if such navigation devices were portable, they werefurther transferable between vehicles and/or useable outside thevehicle, for foot travel for example.

These devices are typically tailored to produce a route of travel basedupon an initial position of the navigation device and a selected/inputtravel destination (end position), noting that the initial positioncould be entered into the device, but is traditionally calculated viaGPS Positioning from a GPS receiver within the navigation device. To aidin navigation of the route, instructions are output along the route to auser of the navigation device. These instructions may be a least one ofaudible and visual.

SUMMARY

The inventors discovered that in certain known areas, or under certainconditions, triggers for output of instructions useable to navigate thetravel route may be blocked. Thus, they have discovered that it would behelpful to the user if these areas or conditions can be eitheranticipated or detected, to permit early output of navigationinstructions.

In at least one embodiment of the present application, a method includesdetermining, during a route of travel of a navigation device, entry ofthe navigation device into a tunnel; and outputting a navigationinstruction to a user of the navigation device within the tunnel, fortravel along the travel route, upon determining, subsequent todetermining entry of the navigation device into the tunnel, at least oneof the tunnel being longer than a first threshold distance, a navigationinstruction being due to be output within a second threshold distance ofan exit of the tunnel and the navigation instruction being due to beoutput within the tunnel.

In at least one embodiment of the present application, a navigationdevice includes a processor to determine, during a route of travel of anavigation device, entry of the navigation device into a tunnel; and anoutput device to output a navigation instruction to a user of thenavigation device within the tunnel, for travel along the travel route,upon the processor determining, subsequent to determining entry of thenavigation device into the tunnel, at least one of the tunnel beinglonger than a first threshold distance, a navigation instruction beingdue to be output within a second threshold distance of an exit of thetunnel and the navigation instruction being due to be output within thetunnel.

In at least one other embodiment of the present application, a methodincludes determining, during travel of a navigation device along atravel route, when a GPS signal is received by a navigation device anddetermining when a GPS signal was not received by the navigation devicefor a period of time exceeding a threshold; and outputting a navigationinstruction to a user of the navigation device, for travel along theroute, upon determining that a GPS signal was not received by thenavigation device for a period of time exceeding a threshold.

In at least one other embodiment of the present application, a deviceincludes a processor to determine, during travel of a navigation devicealong a travel route, when a GPS signal is received by a navigationdevice and to determine when a GPS signal was not received by thenavigation device for a period of time exceeding a threshold; and anoutput device to output a navigation instruction to a user of thenavigation device, for travel along the route, upon the processordetermining that a GPS signal was not received by the navigation devicefor a period of time exceeding a threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

The present application will be described in more detail below by usingexample embodiments, which will be explained with the aid of thedrawings, in which:

FIG. 1 illustrates an example view of a Global Positioning System (GPS);

FIG. 2 illustrates an example block diagram of electronic components ofa navigation device of an embodiment of the present application;

FIG. 3 illustrates an example block diagram of a server, navigationdevice and connection therebetween of an embodiment of the presentapplication;

FIGS. 4A and 4B are perspective views of an implementation of anembodiment of the navigation device;

FIGS. 5A and 5B illustrate example flow charts of embodiments of thepresent application;

FIGS. 6A-C illustrate example flow charts of other embodiments of thepresent application.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentinvention. As used herein, the singular forms “a”, “an”, and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“includes” and/or “including”, when used in this specification, specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

In describing example embodiments illustrated in the drawings, specificterminology is employed for the sake of clarity. However, the disclosureof this patent specification is not intended to be limited to thespecific terminology so selected and it is to be understood that eachspecific element includes all technical equivalents that operate in asimilar manner.

Referencing the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views, exampleembodiments of the present patent application are hereafter described.Like numbers refer to like elements throughout. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

FIG. 1 illustrates an example view of Global Positioning System (GPS),usable by navigation devices, including the navigation device ofembodiments of the present application. Such systems are known and areused for a variety of purposes. In general, GPS is a satellite-radiobased navigation system capable of determining continuous position,velocity, time, and in some instances direction information for anunlimited number of users.

Formerly known as NAVSTAR, the GPS incorporates a plurality ofsatellites which work with the earth in extremely precise orbits. Basedon these precise orbits, GPS satellites can relay their location to anynumber of receiving units.

The GPS system is implemented when a device, specially equipped toreceive GPS data, begins scanning radio frequencies for GPS satellitesignals. Upon receiving a radio signal from a GPS satellite, the devicedetermines the precise location of that satellite via one of a pluralityof different conventional methods. The device will continue scanning, inmost instances, for signals until it has acquired at least threedifferent satellite signals (noting that position is not normally, butcan be determined, with only two signals using other triangulationtechniques). Implementing geometric triangulation, the receiver utilizesthe three known positions to determine its own two-dimensional positionrelative to the satellites. This can be done in a known manner.Additionally, acquiring a fourth satellite signal will allow thereceiving device to calculate its three dimensional position by the samegeometrical calculation in a known manner. The position and velocitydata can be updated in real time on a continuous basis by an unlimitednumber of users.

As shown in FIG. 1, the GPS system is denoted generally by referencenumeral 100. A plurality of satellites 120 are in orbit about the earth124. The orbit of each satellite 120 is not necessarily synchronous withthe orbits of other satellites 120 and, in fact, is likely asynchronous.A GPS receiver 140, usable in embodiments of navigation devices of thepresent application, is shown receiving spread spectrum GPS satellitesignals 160 from the various satellites 120.

The spread spectrum signals 160, continuously transmitted from eachsatellite 120, utilize a highly accurate frequency standard accomplishedwith an extremely accurate atomic clock. Each satellite 120, as part ofits data signal transmission 160, transmits a data stream indicative ofthat particular satellite 120. It is appreciated by those skilled in therelevant art that the GPS receiver device 140 generally acquires spreadspectrum GPS satellite signals 160 from at least three satellites 120for the GPS receiver device 140 to calculate its two-dimensionalposition by triangulation. Acquisition of an additional signal,resulting in signals 160 from a total of four satellites 120, permitsthe GPS receiver device 140 to calculate its three-dimensional positionin a known manner.

FIG. 2 illustrates an example block diagram of electronic components ofa navigation device 200 of an embodiment of the present application, inblock component format. It should be noted that the block diagram of thenavigation device 200 is not inclusive of all components of thenavigation device, but is only representative of many examplecomponents.

The navigation device 200 is located within a housing (not shown). Thehousing includes a processor 210 connected to an input device 220 and adisplay screen 240. The input device 220 can include a keyboard device,voice input device, touch panel and/or any other known input deviceutilized to input information; and the display screen 240 can includeany type of display screen such as an LCD display, for example. In atleast one embodiment of the present application, the input device 220and display screen 240 are integrated into an integrated input anddisplay device, including a touchpad or touchscreen input wherein a userneed only touch a portion of the display screen 240 to select one of aplurality of display choices or to activate one of a plurality ofvirtual buttons.

In addition, other types of output devices 250 can also include,including but not limited to, an audible output device. As output device241 can produce audible information to a user of the navigation device200, it is equally understood that input device 240 can also include amicrophone and software for receiving input voice commands as well.

In the navigation device 200, processor 210 is operatively connected toand set to receive input information from input device 240 via aconnection 225, and operatively connected to at least one of displayscreen 240 and output device 241, via output connections 245, to outputinformation thereto. Further, the processor 210 is operatively connectedto memory 230 via connection 235 and is further adapted to receive/sendinformation from/to input/output (I/O) ports 270 via connection 275,wherein the I/O port 270 is connectable to an I/O device 280 external tothe navigation device 200. The external I/O device 270 may include, butis not limited to an external listening device such as an earpiece forexample. The connection to I/O device 280 can further be a wired orwireless connection to any other external device such as a car stereounit for hands-free operation and/or for voice activated operation forexample, for connection to an ear piece or head phones, and/or forconnection to a mobile phone for example, wherein the mobile phoneconnection may be used to establish a data connection between thenavigation device 200 and the internet or any other network for example,and/or to establish a connection to a server via the internet or someother network for example.

The navigation device 200, in at least one embodiment, may establish a“mobile” network connection with the server 302 via a mobile device 400(such as a mobile phone, PDA, and/or any device with mobile phonetechnology) establishing a digital connection (such as a digitalconnection via known Bluetooth technology for example). Thereafter,through its network service provider, the mobile device 400 canestablish a network connection (through the internet for example) with aserver 302. As such, a “mobile” network connection is establishedbetween the navigation device 200 (which can be, and often times ismobile as it travels alone and/or in a vehicle) and the server 302 toprovide a “real-time” or at least very “up to date” gateway forinformation.

The establishing of the network connection between the mobile device 400(via a service provider) and another device such as the server 302,using the internet 410 for example, can be done in a known manner. Thiscan include use of TCP/IP layered protocol for example. The mobiledevice 400 can utilize any number of communication standards such asCDMA, GSM, WAN, etc.

As such, an internet connection may be utilized which is achieved viadata connection, via a mobile phone or mobile phone technology withinthe navigation device 200 for example. For this connection, an internetconnection between the server 302 and the navigation device 200 isestablished. This can be done, for example, through a mobile phone orother mobile device and a GPRS (General Packet Radio Service)-connection(GPRS connection is a high-speed data connection for mobile devicesprovided by telecom operators; GPRS is a method to connect to theinternet.

The navigation device 200 can further complete a data connection withthe mobile device 400, and eventually with the internet 410 and server302, via existing Bluetooth technology for example, in a known manner,wherein the data protocol can utilize any number of standards, such asthe GSRM, the Data Protocol Standard for the GSM standard, for example.

The navigation device 200 may include its own mobile phone technologywithin the navigation device 200 itself (including an antenna forexample, wherein the internal antenna of the navigation device 200 canfurther alternatively be used). The mobile phone technology within thenavigation device 200 can include internal components as specifiedabove, and/or can include an insertable card, complete with necessarymobile phone technology and/or an antenna for example. As such, mobilephone technology within the navigation device 200 can similarlyestablish a network connection between the navigation device 200 and theserver 302, via the internet 410 for example, in a manner similar tothat of any mobile device 400.

For GRPS phone settings, the Bluetooth enabled device may be used tocorrectly work with the ever changing spectrum of mobile phone models,manufacturers, etc., model/manufacturer specific settings may be storedon the navigation device 200 for example. The data stored for thisinformation can be updated in a manner discussed in any of theembodiments, previous and subsequent.

FIG. 2 further illustrates an operative connection between the processor210 and an antenna/receiver 250 via connection 255, wherein theantenna/receiver 250 can be a GPS antenna/receiver for example. It willbe understood that the antenna and receiver designated by referencenumeral 250 are combined schematically for illustration, but that theantenna and receiver may be separately located components, and that theantenna may be a GPS patch antenna or helical antenna for example.

Further, it will be understood by one of ordinary skill in the art thatthe electronic components shown in FIG. 2 are powered by power sources(not shown) in a conventional manner. As will be understood by one ofordinary skill in the art, different configurations of the componentsshown in FIG. 2 are considered within the scope of the presentapplication. For example, in one embodiment, the components shown inFIG. 2 may be in communication with one another via wired and/orwireless connections and the like. Thus, the scope of the navigationdevice 200 of the present application includes a portable or handheldnavigation device 200.

In addition, the portable or handheld navigation device 200 of FIG. 2can be connected or “docked” in a known manner to a motorized vehiclesuch as a car or boat for example. Such a navigation device 200 is thenremovable from the docked location for portable or handheld navigationuse.

FIG. 3 illustrates an example block diagram of a server 302 and anavigation device 200 of the present application, via a genericcommunications channel 318, of an embodiment of the present application.The server 302 and a navigation device 200 of the present applicationcan communicate when a connection via communications channel 318 isestablished between the server 302 and the navigation device 200 (notingthat such a connection can be a data connection via mobile device, adirect connection via personal computer via the internet, etc.).

The server 302 includes, in addition to other components which may notbe illustrated, a processor 304 operatively connected to a memory 306and further operatively connected, via a wired or wireless connection314, to a mass data storage device 312. The processor 304 is furtheroperatively connected to transmitter 308 and receiver 310, to transmitand send information to and from navigation device 200 viacommunications channel 318. The signals sent and received may includedata, communication, and/or other propagated signals. The transmitter308 and receiver 310 may be selected or designed according to thecommunications requirement and communication technology used in thecommunication design for the navigation system 200. Further, it shouldbe noted that the functions of transmitter 308 and receiver 310 may becombined into a signal transceiver.

Server 302 is further connected to (or includes) a mass storage device312, noting that the mass storage device 312 may be coupled to theserver 302 via communication link 314. The mass storage device 312contains a store of navigation data and map information, and can againbe a separate device from the server 302 or can be incorporated into theserver 302.

The navigation device 200 is adapted to communicate with the server 302through communications channel 318, and includes processor, memory, etc.as previously described with regard to FIG. 2, as well as transmitter320 and receiver 322 to send and receive signals and/or data through thecommunications channel 318, noting that these devices can further beused to communicate with devices other than server 302. Further, thetransmitter 320 and receiver 322 are selected or designed according tocommunication requirements and communication technology used in thecommunication design for the navigation device 200 and the functions ofthe transmitter 320 and receiver 322 may be combined into a singletransceiver.

Software stored in server memory 306 provides instructions for theprocessor 304 and allows the server 302 to provide services to thenavigation device 200. One service provided by the server 302 involvesprocessing requests from the navigation device 200 and transmittingnavigation data from the mass data storage 312 to the navigation device200. According to at least one embodiment of the present application,another service provided by the server 302 includes processing thenavigation data using various algorithms for a desired application andsending the results of these calculations to the navigation device 200.

The communication channel 318 generically represents the propagatingmedium or path that connects the navigation device 200 and the server302. According to at least one embodiment of the present application,both the server 302 and navigation device 200 include a transmitter fortransmitting data through the communication channel and a receiver forreceiving data that has been transmitted through the communicationchannel.

The communication channel 318 is not limited to a particularcommunication technology. Additionally, the communication channel 318 isnot limited to a single communication technology; that is, the channel318 may include several communication links that use a variety oftechnology. For example, according to at least one embodiment, thecommunication channel 318 can be adapted to provide a path forelectrical, optical, and/or electromagnetic communications, etc. Assuch, the communication channel 318 includes, but is not limited to, oneor a combination of the following: electric circuits, electricalconductors such as wires and coaxial cables, fiber optic cables,converters, radio-frequency (rf) waves, the atmosphere, empty space,etc. Furthermore, according to at least one various embodiment, thecommunication channel 318 can include intermediate devices such asrouters, repeaters, buffers, transmitters, and receivers, for example.

In at least one embodiment of the present application, for example, thecommunication channel 318 includes telephone and computer networks.Furthermore, in at least one embodiment, the communication channel 318may be capable of accommodating wireless communication such as radiofrequency, microwave frequency, infrared communication, etc.Additionally, according to at least one embodiment, the communicationchannel 318 can accommodate satellite communication.

The communication signals transmitted through the communication channel318 include, but are not limited to, signals as may be required ordesired for given communication technology. For example, the signals maybe adapted to be used in cellular communication technology such as TimeDivision Multiple Access (TDMA), Frequency Division Multiple Access(FDMA), Code Division Multiple Access (CDMA), Global System for MobileCommunications (GSM), etc. Both digital and analogue signals can betransmitted through the communication channel 318. According to at leastone embodiment, these signals may be modulated, encrypted and/orcompressed signals as may be desirable for the communication technology.

The mass data storage 312 includes sufficient memory for the desirednavigation applications. Examples of the mass data storage 312 mayinclude magnetic data storage media such as hard drives for example,optical storage media such as CD-Roms for example, charged data storagemedia such as flash memory for example, molecular memory, etc.

According to at least one embodiment of the present application, theserver 302 includes a remote server accessible by the navigation device200 via a wireless channel. According to at least one other embodimentof the application, the server 302 may include a network server locatedon a local area network (LAN), wide area network (WAN), virtual privatenetwork (VPN), etc.

According to at least one embodiment of the present application, theserver 302 may include a personal computer such as a desktop or laptopcomputer, and the communication channel 318 may be a cable connectedbetween the personal computer and the navigation device 200.Alternatively, a personal computer may be connected between thenavigation device 200 and the server 302 to establish an internetconnection between the server 302 and the navigation device 200.Alternatively, a mobile telephone or other handheld device may establisha wireless connection to the internet, for connecting the navigationdevice 200 to the server 302 via the internet.

The navigation device 200 may be provided with information from theserver 302 via information downloads which may be periodically updatedupon a user connecting navigation device 200 to the server 302 and/ormay be more dynamic upon a more constant or frequent connection beingmade between the server 302 and navigation device 200 via a wirelessmobile connection device and TCP/IP connection for example. For manydynamic calculations, the processor 304 in the server 302 may be used tohandle the bulk of the processing needs, however, processor 210 ofnavigation device 200 can also handle much processing and calculation,oftentimes independent of a connection to a server 302.

The mass storage device 312 connected to the server 302 can includevolumes more cartographic and route data than that which is able to bemaintained on the navigation device 200 itself, including maps, etc. Theserver 302 may process, for example, the majority of the devices of anavigation device 200 which travel along the route using a set ofprocessing algorithms. Further, the cartographic and route data storedin memory 312 can operate on signals (e.g. GPS signals), originallyreceived by the navigation device 200.

As indicated above in FIG. 2 of the application, a navigation device 200of an embodiment of the present application includes a processor 210, aninput device 220, and a display screen 240. In at least one embodiment,the input device 220 and display screen 240 are integrated into anintegrated input and display device to enable both input of information(via direct input, menu selection, etc.) and display of informationthrough a touch panel screen, for example. Such a screen may be a touchinput LCD screen, for example, as is well known to those of ordinaryskill in the art. Further, the navigation device 200 can also includeany additional input device 220 and/or any additional output device 241,such as audio input/output devices for example.

FIGS. 4A and 4B are perspective views of an implementation of anembodiment of the navigation device 200. As shown in FIG. 4A, thenavigation device 200 may be a unit that includes an integrated inputand display device 290 (a touch panel screen for example) and the othercomponents of FIG. 2 (including but not limited to internal GPS receiver250, microprocessor 210, a power supply, memory systems 220, etc.).

The navigation device 200 may sit on an arm 292, which itself may besecured to a vehicle dashboard/window/etc. using a large suction cup294. This arm 292 is one example of a docking station to which thenavigation device 200 can be docked.

As shown in FIG. 4B, the navigation device 200 can be docked orotherwise connected to an arm 292 of the docking station by snapconnecting the navigation device 292 to the arm 292 for example (this isonly one example, as other known alternatives for connection to adocking station are within the scope of the present application). Thenavigation device 200 may then be rotatable on the arm 292, as shown bythe arrow of FIG. 4B. To release the connection between the navigationdevice 200 and the docking station, a button on the navigation device200 may be pressed, for example (this is only one example, as otherknown alternatives for disconnection to a docking station are within thescope of the present application).

In at least one embodiment, a method of the present application includesdetermining, during a route of travel of the navigation device 200,entry of the navigation device into a tunnel; and outputting anavigation instruction to a user of the navigation device 200 within thetunnel, for travel along the route, upon determining, subsequent todetermining entry of the navigation device 200 into the tunnel, at leastone of the tunnel being longer than a first threshold distance, anavigation instruction being due to be output within a second thresholddistance of an exit of the tunnel and the navigation instruction beingdue to be output within the tunnel.

In at least one embodiment of the present application, a navigationdevice 200 includes a processor 210 to determine, during a route oftravel of the navigation device 200, entry of the navigation device 200into a tunnel; and an output device 241 to output a navigationinstruction to a user of the navigation device within the tunnel, fortravel along the travel route, upon the processor 210 determining,subsequent to determining entry of the navigation device 200 into thetunnel, at least one of the tunnel being longer than a first thresholddistance, a navigation instruction being due to be output within asecond threshold distance of an exit of the tunnel, and the navigationinstruction being due to be output within the tunnel.

With regard to at least one embodiment, the inventors discovered that incertain known areas, or under certain conditions, triggers for output ofinstructions useable to navigate the travel route may be blocked. Thus,they have discovered that it is helpful to the user if these areas orconditions can be either anticipated or detected, to permit early outputof navigation instructions.

An example embodiment of the present application is shown in FIG. 5A. Asshown in FIG. 5A, in step S2 a processor 210 of the navigation device200, for example, determines whether or not the navigation device 200has entered a tunnel. For example, a processor 210 initially receives aninput or selected destination location from a user of the navigationdevice 200. From this, a route can be calculated in a known manner frommap information stored in memory 230, the travel destination, and a GPSlocation of the navigation device 200. Before such route calculation,the map information in the memory 230 can be examined for tunnels and atunnel marker or flag may be set for each tunnel (or the tunnelotherwise identified in the map data utilized by the processor 210 indetermining the route) such that the processor 210 of the navigationdevice 200 can recognize, during route calculation for example, if auser will drive on a route including a tunnel. For example, points ornodes on the map information is traditionally marked, so for a tunnel, aline of travel between two nodes of the tunnel, on stored mapinformation, may be “flagged” or otherwise marked. Nodes are usuallymarked at junctions and therefore an entire stretch of map informationbetween two junctions may be marked as a tunnel. Thus, during travelalong the route, the processor 210 can determine if a user of thenavigation device 200 is currently driving along a navigation route witha tunnel, based upon marker(s)/flag(s) set.

Thereafter, in step S4, S6, S7 and S8, it may be determined, by theprocessor 210 for example, whether or not at least one other conditionhas been met. It should be noted that the order of steps S4, S6, S7 andS8 is not important, as the processor 210 can determine each of thevarious conditions in any order.

In step S4, it may be determined, by the processor 210 for example,whether or not the tunnel is longer than a threshold “x” distance. Forexample, if the tunnel is only a short distance, then it is most likelythat no output of instructions will be needed while the navigationdevice 200 is still located in the tunnel. Such a threshold distance canbe set in the map information such that, for example, the tunnel is onlyflagged if it is longer than a certain threshold distance.Alternatively, the tunnel flag may be set for all tunnels, and then thelength later compared to the threshold by the processor 210 duringnavigation. Such a threshold distance can be, for example, two miles. Itshould be noted that such a step S4 is optional, when at least one ofsteps S6 and S8 are utilized. Thus, if the processor 210 determines thatthe tunnel is longer than a threshold “x” distance, the processor 210will instruct output of the instruction (likely within the tunnel forexample) in step S10.

In step S6, it may be determined, by the processor 210 for example,whether or not a navigation instruction is due to be output within athreshold “y” distance after an exit of the tunnel. For example, theprocessor 210 knows when a next instruction is due to be output andnormally outputs an instruction based upon a received GPS signal at acertain map location. This may be achieved in a known manner. As such,if the processor 210 knows an instruction is due to be output within,for example, one mile of (measured from or occurring after) an exit ofthe tunnel, and the processor 210 knows that the navigation device 200is currently located in a tunnel wherein a GPS signal will likely belost, the GPS signal may not be recovered in time for the processor 210of the navigation device 200 to timely output the instruction. Thus, ifa navigation instruction is due to be output within a thresholddistance, such as one mile for example, of an exit of the tunnel, theprocessor 210 will instruct output of the instruction within the tunnelin step S10, so that the user has adequate warning of an upcoming turn,merge, entry onto a highway, etc. which will occur after exit of thetunnel. It should be noted that such a step S6 is optional, when atleast one of steps S4 and S8 are utilized.

Finally, in step S8, it may be determined, by the processor 210 forexample, whether or not a navigation instruction is due to be outputwithin the tunnel. For example, in some tunnels such as those inBrussels, Belgium for example, junctions may be included within thetunnel. If this is the case, then such an instruction needs to be outputto the user within the tunnel itself in step S10. This condition can bedetected in a manner similar to that set forth above regarding steps S4and S6 by the processor 210, to provide output in step S10 upon thecondition being met. It should be noted that such a step S8 is optional,when at least one of steps S4 and S6 are utilized.

Thus, in a method of an example embodiment of the present application,entry of the navigation device 200 into a tunnel can be determined instep S2 by the processor 210, during a route of travel of the navigationdevice 200, and a navigation instruction can be output within the tunnelin step S10, for travel along the route, upon the processor 210determining, subsequent to determining entry of the navigation device200 into the tunnel, at least one of the tunnel being longer than afirst threshold distance in step S4, a navigation instruction being dueto be output within a second threshold distance of an exit of the tunnelin step S6, and/or the navigation instruction being due to be outputwithin the tunnel in step S8.

The output of the navigation instruction in step S10 can include atleast one of a visual output of the navigation instruction, on anintegrated input and display device 290 of the navigation device 200 forexample, and/or an audible output of the navigation instruction, via aspeaker within the navigation device 200 for example.

FIG. 5B illustrates a further example embodiment of the presentapplication. In step S12, the travel route of the navigation device 200is initially determined, by processor 210 for example, upon receipt of atravel destination. For example, once the travel destination is selectedor input for example, a travel route can be determined in a known mannerutilizing a received GPS signal indicating a current location of thenavigation device, stored map information, and the received traveldestination as described above.

Thereafter, it can be determined in step S14, by processor 210 forexample, whether or not the particular route of travel determined willinclude travel through a tunnel. Again, the tunnel may be something thatis flagged in memory 230 and then detectable by the processor 210 forexample, upon determining the route of travel. If the route of travelwill not involve travel through a tunnel, then the travel route may beoutput and the instructions may be output in a normal manner in stepS16, taking into consideration any other reasons to output or not outputthe instructions of course.

If the answer to step S14 is yes, then it can be determined in step S18by the processor 210 for example, whether or not the navigation device200 has entered the tunnel in a manner somewhat similar to that setforth in FIG. 5A for example. Subsequent steps S20, S22, S23, S24, andS26 of FIG. 5B can occur in a manner similar to that previouslydescribed with regard to respective steps S4, S6, S8, and S10 of FIG.5A. It should be noted that the order of steps S20, S22, S23 and S24 isnot important, as the processor 210 can determine each of the variousconditions in any order.

It should further be noted that the determining of entry of thenavigation device 200 into the tunnel of FIGS. 5A and 5B can furtherinclude a step of the processor 210 determining a lack of receipt of aGPS signal, normally useable to indicate a current location of thenavigation device 200, for a period of time exceeding the threshold. Forexample, the processor 210 can first determine that the GPS signal hasnot been received for a period of time, such as three seconds forexample, and if so, the processor 210 can then determine whether or notthe navigation device 200 has entered the tunnel in the mannerpreviously described.

In such an instance, in step S7 of FIG. 5A or step S23 of FIG. 5B, itmay be determined, by the processor 210 for example, whether or not anavigation instruction is due to be output within a threshold “z”distance of an estimated current position of the navigation device 200.Thus, if the processor 210 determine a lack of receipt of a GPS signalfor a period of time exceeding the threshold, for example three seconds,the processor 210 can then determine in step S7 of FIG. 5A or step S23of FIG. 5B, whether or not a next instruction is due to be output withina threshold “z” distance of an estimated current position of thenavigation device 200 (noting that the processor 200 can determine anestimated current position of the vehicle in which the navigation deviceis located based upon a last known GSP position signal received, a lastknown speed of the vehicle and time passed since a valid GPS signal wasreceived). If the answer is yes, the processor 210 will instruct outputof the instruction (likely within the tunnel for example) in step S10.Such a threshold “z” can be, for example, two miles, wherein aninstruction is output upon the processor 210 determining an instructionis due to be output within two miles of a current position of thenavigation device 200. It should be noted that such a step S7 or S23 isoptional, when at least one of steps S4, S6 and S8 are utilized, and itshould be noted that any of steps S4, S6, and S8 or steps S20, S22 andS24 are optional when respectively S7 or S23 are utilized in conjunctionwith the determination of the lack of a GPS signal for a threshold timeperiod.

It should further be noted that the processor 210 determining of thelack of receipt of a GPS signal may include storing a time at which thenavigation device 200 receives a GPS signal, and counting the time aftera GPS signal is received, and comparing the count to the threshold todetermine whether or not the threshold has been exceeded. Such steps canbe included in either of the processes shown in FIGS. 5A and 5B forexample.

Regarding the various distance thresholds described in steps S4 and S6,these thresholds may be the same or equal, or may further be different.For example, the distance threshold in steps S4 of FIG. 5A and S20 ofFIG. 5B may be a relatively longer distance than the distance thresholdset in steps S6 of FIG. 5A and S24 of FIG. 5B, as it may be desirable tooutput navigation instructions within a tunnel only if a tunnel is of agreat distance or great length, wherein it may further be desirable tooutput navigation instructions within a tunnel if another or nextinstruction is due to be output to the user within only a short distanceof the exit of the tunnel.

It should be noted that each of the aforementioned aspects of anembodiment of the present application have been described with regard tothe method of the present application. However, at least one embodimentof the present application is directed to a navigation device 200,including a processor 210 to determine, during a route of travel of anavigation device 200, entry of the navigation device 200 into a tunnel;and an output device 241 to output a navigation instruction to a user ofthe navigation device 200 within the tunnel, for travel along the travelroute, upon the processor 210 determining, subsequent to determiningentry of the navigation device 200 into the tunnel, at least one of thetunnel being longer than a first threshold distance, a navigationinstruction being due to be output within a second threshold distance ofan exit of the tunnel and the navigation instruction being due to beoutput within the tunnel. Such a processor 210 may enable options and/orenable display of icons, upon receipt of an indication of selection ofoptions. Thus, such a navigation device 200 may be used to perform thevarious aspects of the method described with regard to FIGS. 5A and 5B,as would be understood by one of ordinary skill in the art. Thus,further explanation is omitted for the sake of brevity.

In at least one embodiment of the present application, a method includesdetermining, during travel of a navigation device 200 along a travelroute, when a GPS signal is received by a navigation device 200 anddetermining when a GPS signal is not received by the navigation device200 for a period of time exceeding the threshold. The method furtherincludes outputting a navigation instruction to a user of the navigationdevice 200, for travel along the route, upon determining that a GPSsignal was not received by the navigation device 200 for a period oftime exceeding the threshold.

In at least one embodiment of the present application, a navigationdevice 200 includes a processor 210 to determine, during travel of anavigation device 200 along a travel route, when a GPS signal isreceived by a navigation device 200 and to determine when a GPS signalwas not received by the navigation device 200 for a period of timeexceeding a threshold. An output device 241 is further included tooutput a navigation instruction to a user of the navigation device 200,for travel along the route, upon the processor 210 determining that aGPS signal was not received by the navigation device 200 for a period oftime exceeding the threshold.

FIG. 6A illustrates an example embodiment of the present application. Inthis example embodiment, in step S30, it is initially determined, by theprocessor 210 for example, whether or not a GPS signal was received. Ifso, the system proceeds back to repeat step S30, assuming thisdetermination occurs during travel of a navigation device 200 along atravel route.

If it is determined that a GPS signal was not received by the navigationdevice 200, the process moves to step S32 where it is determined, by theprocessor 210 for example, whether or not a threshold time was exceeded,namely, whether or not the GPS signal was not received by the navigationdevice 200 for a period of time exceeding a threshold.

If it is determined that a GPS signal was not received by the navigationdevice 200 for a period of time exceeding the threshold in step S32,then the processor 210 moves to step S34, wherein a navigationinstruction is output by an output device 241 of the navigation device200, to a user of the navigation device 200. It should be understoodthat the steps S30 and S32 may be performed by a processor 210 of thenavigation device 200 for example. Further, the output of the navigationinstruction by an output device 241 may include at least one of adisplay of the navigation instruction, by an integrated input anddisplay device 290 of the navigation device 200 for example, and/or anaudible output of the navigation instruction, via a speaker or otheraudible output device of the navigation device 200 for example.

FIG. 6B describes a further embodiment of the present application. Inthis embodiment, it is determined whether or not a GPS signal wasreceived. If so, the process moves to step S42 wherein the GPS signal isstored in memory 230 for example, thereby storing a current location ofthe navigation device 200. Once the GPS signal is received, a counter isreset in step S44 to begin counting. The process then cycles back tostep S40.

If it is determined in step S40 that a GPS signal was not received, bythe processor 210 of the navigation device 200 for example, a currentcount can be compared in step S46 by the processor 210 to a threshold(such as the threshold time of step S32 of FIG. 6A for example).Thereafter, in step S48, it can be determined by the processor 210 forexample, whether or not the threshold is exceeded in step S48. If so,the navigation instruction may be output in step S52 in a mannersomewhat similar to that previously described. If not, the count isupdated in step S50 and it is again determined whether or not the GPSsignal is received in step S40.

Alternatively, the processor 210 can check a difference in time betweena current time and a time at which a last GPS signal was received. Forexample, a GPS module of the navigation device 200 may send out aposition signal every second, and with that position it may send out aflag to determine whether it was valid or not. Thereafter the processor210 can count the number of invalidity flagged GPS positions, instead ofcomparing a time between a current time and a time when a last valid GPSsignal was received.

FIG. 6C describes a further alternative embodiment of the presentapplication. Initially, it is determined in step S60 whether or not aGPS signal was received. If it is determined that a GPS signal wasreceived, then the system cycles back to step S60. However, if it isdetermined that a GPS signal was not received by the navigation device200, it is determined in step S62, by the processor 210 for example,whether or not a threshold time was exceeded since a last receipt of aGPS signal. If not, the process cycles back to step S60.

However, if it is determined, by the processor 210 of the navigationdevice 200 for example, that a GPS signal was not received by thenavigation device 200 for a period of time exceeding a threshold, theprocess moves to step S64. In Step S64, it is determined whether or notthe navigation device 200 is traveling along a portion of the travelroute proximate to a known area of GPS signal loss. Such an area may bea flagged area detectable by the processor 210 in a manner similarlydescribed with regard to the tunnel in FIGS. 5A and 5B for example,wherein such a line of travel between two nodes on stored mapinformation is “flagged” or otherwise marked, similar to the marking ofa tunnel for example. Nodes are usually marked at junctions andtherefore an entire stretch of map information between two junctions maybe marked as a known area of GPS signal loss (although tunnels can occurbetween nodes, as well). Such an area may be at least one of a tunnel, amountain, an underpass, a canyon, an urban canyon, etc. Again, the knownarea of GPS signal loss may be flagged in a manner similar to thatpreviously discussed with regard to the tunnel in FIGS. 5A and 5B of thepresent application for example.

The processor 210 may determine, in step S64, whether or not the knownarea of GPS signal loss is proximate to a current location of thenavigation device 200 by the processor 210 determining whether or not alast known GPS location of the navigation device 200 is within athreshold distance of the known area of GPS signal loss. If the answerto step S64 is no, the method proceeds back to step S60. However, if theanswer is yes, a next navigation instruction is output in step S66,namely upon the processor 210 determining that the navigation device 200is traveling along a portion of the travel route proximate to a knownarea of GPS signal loss.

As nodes are usually marked at junctions and therefore an entire stretchof map information between two junctions may be marked as a known areaof GPS signal loss. Such an area may be at least one of a tunnel, amountain, an underpass, a canyon, an urban canyon, etc. Again, the knownarea of GPS signal loss may be flagged in a manner similar to thatpreviously discussed with regard to the tunnel in FIGS. 5A and 5B of thepresent application for example, such that when the GPS signal is lostduring such an area of travel, it will be presumed by the processor 210that it was due to entrance to a tunnel, mountain, underpass, canyon, anurban canyon etc.

It should be noted that the output of the navigation instruction in stepS66 normally occurs within the known area of GPS signal loss. However,this does not have to be the case. For example, an instruction may beoutput within a threshold time period after GPS signal loss, such as 3seconds after the entering the known area of GPS signal loss forexample. However, this could be tied to other parameters, for example,such as if a next instruction is due to be output within a thresholddistance of an exit of the known area of GPS signal loss or within athreshold distance of an estimated current position of the navigationdevice 200 (noting that the processor 200 can determine an estimatedcurrent position of the vehicle in which the navigation device islocated based upon a last known GSP position signal received, a lastknown speed of the vehicle and time passed since a valid GPS signal wasreceived).

Further, in at least one other embodiment of the present application,the output in step S66 can be conditioned, by the processor 210determining, for example, that a navigation instruction is due to beoutput within a threshold “z” distance of an estimated current positionof the navigation device 200. Thus, if the processor 210 determines alack of receipt of a GPS signal for a period of time exceeding thethreshold in step S62, for example three seconds, the processor 210 canthen determine whether or not a next instruction is due to be outputwithin a threshold “z” distance of an estimated current position of thenavigation device 200 (noting that the processor 200 can determine anestimated current position of the vehicle in which the navigation deviceis located based upon a last known GSP position signal received, a lastknown speed of the vehicle and time passed since a valid GPS signal wasreceived). If the answer is yes, the processor 210 will instruct outputof the instruction (likely within the tunnel for example) in step S66.Such a threshold “z” can be, for example, two miles, wherein aninstruction is output upon the processor 210 determining an instructionis due to be output within two miles of a current position of thenavigation device 200.

In any of the aforementioned embodiments of the present application, anavigation instruction may be adjusted prior to output, to compensatefor a period of time when the GPS signal was determined not to bereceived. For example, if an instruction was due to be output uponexiting of a tunnel for example, and it is known that the instructionwas to be output within a certain distance of an exit, a highwayentrance, any other particular turn, etc., the next instruction may beoutput within the tunnel early in step S10 of FIG. 5A for example, afterbeing adjusted by increasing a distance parameter for example. Forexample, instead of stating that “after 100 meters turn right,” thenavigation instruction may be adjusted, prior to output to compensatefor the period of time when the GPS signal was determined not to bereceived. For example, instruction may be output as “after 500 metersturn right.” The navigation device 200 keeps updating position basedupon the last known GPS position and the last known instruction. Thus,the adjustment of the navigation instruction may be done by theprocessor 210, for example, based upon a last know GPS location, alocation at which an instruction was supposed to be output, and adistance traveled (based upon a speed of travel and a time passingbetween when the last GPS signal was received). For example, if thevehicle in which the navigation device 200 is located is traveling at 20meters/second, GPS signal loss occurs 1000 meters before a next turn isdue, for example, instead of outputting an instruction saying “turnright in 1000 meters”, if the instruction is given 5 seconds afterloosing the GPS signal, it will be adjusted to “turn right in 900meters” as it assumes that the vehicle traveled another 100 meters inthose 5 seconds.

It should be noted that each of the aforementioned aspects of anembodiment of the present application have been described with regard tothe method of the present application. However, at least one embodimentof the present application is directed to a navigation device 200,including a processor 210 to determine, during travel of a navigationdevice 200 along a travel route, when a GPS signal is received by anavigation device 200 and to determine when a GPS signal was notreceived by the navigation device 200 for a period of time exceeding athreshold. An output device 241 is further included to output anavigation instruction to a user of the navigation device 200, fortravel along the route, upon the processor 210 determining that a GPSsignal was not received by the navigation device 200 for a period oftime exceeding the threshold. Such a processor 210 may enable optionsand/or enable display of icons, upon receipt of an indication ofselection of options. Thus, such a navigation device 200 may be used toperform the various aspects of the method described with regard to FIGS.6A-C, as would be understood by one of ordinary skill in the art. Thus,further explanation is omitted for the sake of brevity.

The methods of at least one embodiment expressed above may beimplemented as a computer data signal embodied in the carrier wave orpropagated signal that represents a sequence of instructions which, whenexecuted by a processor (such as processor 304 of server 302, and/orprocessor 210 of navigation device 200 for example) causes the processorto perform a respective method. In at least one other embodiment, atleast one method provided above may be implemented above as a set ofinstructions contained on a computer readable or computer accessiblemedium, such as one of the memory devices previously described, forexample, to perform the respective method when executed by a processoror other computer device. In varying embodiments, the medium may be amagnetic medium, electronic medium, optical medium, etc.

Even further, any of the aforementioned methods may be embodied in theform of a program. The program may be stored on a computer readablemedia and is adapted to perform any one of the aforementioned methodswhen run on a computer device (a device including a processor). Thus,the storage medium or computer readable medium, is adapted to storeinformation and is adapted to interact with a data processing facilityor computer device to perform the method of any of the above mentionedembodiments.

The storage medium may be a built-in medium installed inside a computerdevice main body or a removable medium arranged so that it can beseparated from the computer device main body. Examples of the built-inmedium include, but are not limited to, rewriteable non-volatilememories, such as ROMs and flash memories, and hard disks. Examples ofthe removable medium include, but are not limited to, optical storagemedia such as CD-ROMs and DVDs; magneto-optical storage media, such asMOs; magnetism storage media, including but not limited to floppy disks(trademark), cassette tapes, and removable hard disks; media with abuilt-in rewriteable non-volatile memory, including but not limited tomemory cards; and media with a built-in ROM, including but not limitedto ROM cassettes; etc. Furthermore, various information regarding storedimages, for example, property information, may be stored in any otherform, or it may be provided in other ways.

As one of ordinary skill in the art will understand upon reading thedisclosure, the electronic components of the navigation device 200and/or the components of the server 302 can be embodied as computerhardware circuitry or as a computer readable program, or as acombination of both.

The system and method of embodiments of the present application includesoftware operative on the processor to perform at least one of themethods according to the teachings of the present application. One ofordinary skill in the art will understand, upon reading andcomprehending this disclosure, the manner in which a software programcan be launched from a computer readable medium in a computer basedsystem to execute the functions found in the software program. One ofordinary skill in the art will further understand the variousprogramming languages which may be employed to create a software programdesigned to implement and perform at least one of the methods of thepresent application.

The programs can be structured in an object-orientation using anobject-oriented language including but not limited to JAVA, Smalltalk,C++, etc., and the programs can be structured in aprocedural-orientation using a procedural language including but notlimited to COBAL, C, etc. The software components can communicate in anynumber of ways that are well known to those of ordinary skill in theart, including but not limited to by application of program interfaces(API), interprocess communication techniques, including but not limitedto report procedure call (RPC), common object request brokerarchitecture (CORBA), Component Object Model (COM), DistributedComponent Object Model (DCOM), Distributed System Object Model (DSOM),and Remote Method Invocation (RMI). However, as will be appreciated byone of ordinary skill in the art upon reading the present applicationdisclosure, the teachings of the present application are not limited toa particular programming language or environment.

The above systems, devices, and methods have been described by way ofexample and not by way of limitation with respect to improving accuracy,processor speed, and ease of user interaction, etc. with a navigationdevice 200.

Further, elements and/or features of different example embodiments maybe combined with each other and/or substituted for each other within thescope of this disclosure and appended claims.

Still further, any one of the above-described and other example featuresof the present invention may be embodied in the form of an apparatus,method, system, computer program and computer program product. Forexample, of the aforementioned methods may be embodied in the form of asystem or device, including, but not limited to, any of the structurefor performing the methodology illustrated in the drawings.

Example embodiments being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the present invention, andall such modifications as would be obvious to one skilled in the art areintended to be included within the scope of the following claims.

What is claimed is:
 1. A method, comprising: determining, during a routeof travel of a navigation device, entry of the navigation device into atunnel; and outputting a navigation instruction to a user of thenavigation device within the tunnel, for travel along the travel route,upon determining, subsequent to determining entry of the navigationdevice into the tunnel, at least one of the tunnel being longer than afirst threshold distance, a navigation instruction being due to beoutput within a second threshold distance of an exit of the tunnel andthe navigation instruction being due to be output within the tunnel. 2.The method of claim 1, wherein the output includes at least one of avisual output of the navigation instruction and an audible output of thenavigation instruction.
 3. The method of claim 1, further comprisingdetermining the travel route of the navigation device upon receipt of atravel destination.
 4. The method of claim 1, wherein the determining ofentry of the navigation device into the tunnel includes determining alack of receipt of a GPS signal, normally useable to indicate a currentlocation of the navigation device, for a period of time exceeding athreshold.
 5. The method of claim 4, wherein the determining of thedetermining lack of receipt of a GPS signal includes storing a time atwhich the navigation device receives a GPS signal, counting a time aftera GPS signal is received, and comparing the count to the threshold todetermine whether or not the threshold has been exceeded.
 6. The methodof claim 3, wherein the determining of entry of the navigation deviceinto the tunnel includes determining a lack of receipt of a GPS signal,normally useable to indicate a current location of the navigationdevice, for a period of time exceeding a threshold.
 7. The method ofclaim 6, wherein the determining of the determining lack of receipt of aGPS signal includes storing a time at which the navigation devicereceives a GPS signal, counting a time after a GPS signal is received,and comparing the count to the threshold to determine whether or not thethreshold has been exceeded.
 8. The method of claim 1, furthercomprising determining when the travel route of the navigation devicewill involve travel through a tunnel, wherein the determining of tunnelentry is subsequent to determining that the travel route of thenavigation device will involve travel through a tunnel.
 9. The method ofclaim 3, further comprising determining when the determined travel routewill involve travel through a tunnel, wherein the determining of tunnelentry is subsequent to determining that the travel route of thenavigation device will involve travel through a tunnel.
 10. The methodof claim 1, wherein the navigation instruction is adjusted, prior tooutput, to compensate for output within the tunnel.
 11. The method ofclaim 1, wherein the first and second thresholds are equal.
 12. Acomputer readable medium including program segments for, when executedon a processor of a navigation device, causing the navigation device toimplement the method of claim
 1. 13. A method, comprising: determining,during travel of a navigation device along a travel route, when a GPSsignal is received by a navigation device and determining when a GPSsignal was not received by the navigation device for a period of timeexceeding a threshold; and outputting a navigation instruction to a userof the navigation device, for travel along the route, upon determiningthat a GPS signal was not received by the navigation device for a periodof time exceeding the threshold.
 14. The method of claim 13, wherein theoutput includes at least one of display of the navigation instructionand an audible output of the navigation instruction.
 15. The method ofclaim 13, wherein the navigation instruction is adjusted, prior tooutput, to compensate for the period of time when the GPS signal wasdetermined not to be received.
 16. The method of claim 13, wherein thedetermining includes storing a time at which the navigation devicereceives a GPS signal, counting a time after a GPS signal is received,and comparing the count to the threshold to determine whether or not thethreshold has been exceeded.
 17. The method of claim 13, furthercomprising determining, upon determining that a GPS signal was notreceived by the navigation device for a period of time exceeding athreshold, whether or not the navigation device is traveling along aportion of the travel route proximate to a known area of GPS signalloss, the navigation instruction being output upon determining that thenavigation device is traveling along a portion of the travel routeproximate to a known area of GPS signal loss.
 18. The method of claim13, further comprising determining, upon determining that a GPS signalwas not received by the navigation device for a period of time exceedinga threshold, whether or not a navigation instruction is due to be outputwithin a threshold distance of an estimated current position of thenavigation device, the navigation instruction being output upondetermining that a next instruction is due to be output within athreshold distance of an estimated current position of the navigationdevice.
 19. The method of claim 17, wherein the known area of GPS signalloss is flagged.
 20. The method of claim 17, wherein the known area ofGPS signal loss includes at least one of a tunnel, a mountain, anunderpass, a canyon and an urban canyon.
 21. A computer readable mediumincluding program segments for, when executed on a processor of anavigation device, causing the navigation device to implement the methodof claim
 13. 22. A navigation device, comprising: a processor todetermine, during a route of travel of a navigation device, entry of thenavigation device into a tunnel; and an output device to output anavigation instruction to a user of the navigation device within thetunnel, for travel along the travel route, upon the processordetermining, subsequent to determining entry of the navigation deviceinto the tunnel, at least one of the tunnel being longer than a firstthreshold distance, a navigation instruction being due to be outputwithin a second threshold distance of an exit of the tunnel and thenavigation instruction being due to be output within the tunnel.
 23. Thenavigation device of claim 22, wherein the output device includes atleast one of a display to visually display the navigation instructionand an audible output device to audibly output the navigationinstruction.
 24. The navigation device of claim 22, wherein theprocessor is further useable to determine the travel route of thenavigation device, upon receipt of a travel destination.
 25. Thenavigation device of claim 22, wherein the determining of entry of thenavigation device into the tunnel includes the processor determining alack of receipt of a GPS signal, normally useable to indicate a currentlocation of the navigation device, for a period of time exceeding athreshold.
 26. The navigation device of claim 25, wherein thedetermining of the determining lack of receipt of a GPS signal by theprocessor includes use of a memory of the navigation device to store atime at which the navigation device receives a GPS signal, and use ofthe processor to count a time after a GPS signal is received and comparethe count to the threshold to determine whether or not the threshold hasbeen exceeded.
 27. The navigation device of claim 24, wherein thedetermining of entry of the navigation device into the tunnel by theprocessor includes determining a lack of receipt of a GPS signal,normally useable to indicate a current location of the navigationdevice, for a period of time exceeding a threshold.
 28. The navigationdevice of claim 27, wherein the determining of the determining lack ofreceipt of a GPS signal includes use of a memory of the navigationdevice to store a time at which the navigation device receives a GPSsignal, and use of the processor to count a time after a GPS signal isreceived and compare the count to the threshold to determine whether ornot the threshold has been exceeded.
 29. The navigation device of claim22, wherein the processor is further useable to determine when thetravel route of the navigation device will involve travel through atunnel, wherein the processor determines tunnel entry subsequent to theprocessor determining that the travel route of the navigation devicewill involve travel through a tunnel.
 30. The navigation device of claim24, wherein the processor is further useable to determine when thetravel route of the navigation device will involve travel through atunnel, wherein the processor determines tunnel entry subsequent to theprocessor determining that the travel route of the navigation devicewill involve travel through a tunnel.
 31. The navigation device of claim22, wherein the navigation instruction is adjusted by the processor,prior to output, to compensate for output within the tunnel.
 32. Thenavigation device of claim 22, wherein the first and second thresholdsare equal.
 33. A navigation device, comprising: a processor todetermine, during travel of a navigation device along a travel route,when a GPS signal is received by a navigation device and to determinewhen a GPS signal was not received by the navigation device for a periodof time exceeding a threshold; and an output device to output anavigation instruction to a user of the navigation device, for travelalong the route, upon the processor determining that a GPS signal wasnot received by the navigation device for a period of time exceeding thethreshold.
 34. The navigation device of claim 33, wherein the outputdevice includes at least one of a display to visually display thenavigation instruction and an audible output device to audibly outputthe navigation instruction.
 35. The navigation device of claim 33,wherein the navigation instruction is adjusted by the processor, priorto output, to compensate for the period of time when the GPS signal wasdetermined not to be received.
 36. The navigation device of claim 33,wherein the determining of the determining lack of receipt of a GPSsignal includes use of a memory of the navigation device to store a timeat which the navigation device receives a GPS signal, and use of theprocessor to count a time after a GPS signal is received and compare thecount to the threshold to determine whether or not the threshold hasbeen exceeded.
 37. The navigation device of claim 33, wherein theprocessor is further useable to determine, upon determining that a GPSsignal was not received by the navigation device for a period of timeexceeding a threshold, whether or not the navigation device is travelingalong a portion of the travel route proximate to a known area of GPSsignal loss, the navigation instruction being output by the outputdevice upon determining that the navigation device is traveling along aportion of the travel route proximate to a known area of GPS signalloss.
 38. The navigation device of claim 37, wherein the known area ofGPS signal loss is flagged.
 39. The navigation device of claim 37,wherein the known area of GPS signal loss includes at least one of atunnel, a mountain, an underpass, a canyon and an urban canyon.
 40. Thenavigation device of claim 33, wherein the processor is further useableto determine, upon determining that a GPS signal was not received by thenavigation device for a period of time exceeding a threshold, whether ornot a navigation instruction is due to be output within a thresholddistance of an estimated current position of the navigation device, thenavigation instruction being output by the output device upondetermining that a next instruction is due to be output within athreshold distance of an estimated current position of the navigationdevice.